Fastener applying machine



Jan. 12, 1960 s. KUFEL, JR., ETAI- F'ASTENER APPLYING MACHINE Filed Sept. ll, 1958 5 Sheets-sheet 1 mummmmmmwmmulw 6? FIG.3

www@ ATTORNEYS. y

Jan. 12,'1960 s. KUFEI., JR., ETAL 2,920,324

FASTENER APPLYING MACHINE Filed Sept. l1, 1958 5 Sheets-Sheet 2 65 i f/ M 65 ATTORNEYS.

2,920,324 ce Patented Jan. 1 2., 1.960-

FASTENER APPLYING MACHINE Smith, Hope Stanley Kufel, Jr., Warwick, and George M.

East Green- Valley, RJ., assignors to Bostitch, Inc., wich, RJ., a corporation of Rh'ode Island This invention relates to improvements in fastenerapplying machines for attaching together various articles and objects by the use of'fasteners such as U-shaped staples or the like.

vOne object of the invention is to provide an implement of simple and compact construction capable of being produced by economical methods of manufacture to reduce its cost yet eicient and durable in use over long periods of time.

Another object is to provide a new and improved form of construction of the driving means for the fasteners or staples to insure accurate engagement of the staple-driver with a single staple during each stroke thereof without interference from other staples in the supply.

Another object is to provide improved means for guid. ing the staple-driver throughout its driving stroke to cause it toengage the head of a staple accurately without contact with the head of another adjacent staple in the stick or refill supply.

Another object is to pro-vide improved guiding means Y for the driver to avoid use of a narrow parallel-sided raceway or throat for confining the driver to a straight path during reciprocation thereof. Y

Another object is to simplify and reduce the cost of manufacture of the implement by a form of construction that eliminates the need for close tolerances in the dimensionsvfor machining and finishing the parts of the implement.

Another object is to improve the structure of the implement and render it proof against faulty action or inoperativeness by jamming and clogging of the staples or other fasteners therein.

Further objects of the invention are set forth in, or will appear from, thev following specication which describesy a preferred form of construction of the implement, by way of example, drawings. ln the drawings:

Fig. 1 is a side elevational view of a manually-operable stapling implement embodyingthe present invention;

Fig. 2 is a similar view of the implement showing its operating lever and staple-magazine in vertical section to illustrate the driving elements associated therewith in their elevated relationship relatively to the base of the machine;

Fig. 3 is a similar View showing the operating lever and staple-magazine in-longitudinal section with the-assembled driving means illustrated in depressed relationship at the completion of driving a staple; i

Fig. 4 is an enlarged top plan view of .the fore part of the staple-magazine shown with its vside Vwalls in section at the front and illustrating the staple-core andthe throat through which the staples-are driven; l

Fig. 5 is an enlarged top plan View of the pivotalaeonnection ,between the staple-magazine andthe operating lever shown with the lever thrown back to uncover Ithe magazine for loading it with staple.

Fig.- 6 i'S a' Similarly enlarged bcttomvplanview in ta'nsas illustrated by the accompanying verse section of the forward end of the operating lever'of 2 the implement showing the staple-driver mounted thereon and the guiding element for dening and controlling its stroke;

Fig. 7 is an enlarged transverse sectional view of the operating parts of the machine taken on line 7-7 of Fig. 2;

Fig. S is a similar sectional View taken on line 8-.8 of Fig. 2;

Fig. 9 is a similar sectional View taken on line 9--9 of Fig. l;

Fig. l0 is a more complete sectional view taken on line 10--10 of Fig. 2 and showing the vbase and the yoke thereon for mounting the magazine and operating lever;

Fig. 11 is a transverse sectional view on line 1 1-11 of Fig. 2 showing in detail the pivotal mounting of the several cooperating parts; and

Fig. l2 is a perspective View of the driver-guiding element shown as disassembled from the machine.

The invention is herein described and illustrated as embodied in a stapling implement of generally conventional type such as an manually-operable desk stapler. It is to be understood, however, that the presentimprovements are adapted for use with other forms of stapling and stitching machines to secure the benefits inherent therein. Referring to Fig. 1, the implement may comprise a base or mounting 2 for supporting a clinching anvil 3 at its forward end; or, in other applications for plier and like types of machines, the anvil may bemounted on any suitable support or even dispensed with in hammertype Staplers.

In the present form of construction the rearward end of the base 2 has suitably fastened thereto a U-shaped yoke 4-with its sides projecting thereabove for eradling and hingedly supporting a hollow magazine arm 5 adapted to contain a supply of staples s or similar fastener ele.- ments. The magazine 5 is pivotally mounted on the base 2 at its rearward end by means of a crosspin 6 extending through holes in its sides and the sides of the yoke 4 (Figs. 3, 4). Also pivoted on the pin 6 is operating lever 7 of inverted U-shape arranged with its side walls 8 overlapping the sides of the magazine 5 and perforated with holes for receiving the ends ofthe pin 6. The lever 7 extends forwardly with its upper wall arched in a graceful curve and its front end surmounted by a hand-rest 9 of ornamental design.

The magazine 5 may be constructed of sheet-metal The forward ends of the side walls 10 are extended upwardly and inclined outwardly (Fig. entrant opening for guiding the staple-driver laterally in its descent. A keeper lug or detent 14 formed on one side wall 10 of the magazine 5 projects laterally therefrom for engagement with a latch, later described, that is slidably mounted on the operatinglever 7 for releasably connecting these parts.

As usually arranged, a U-shaped rail or staple-core 15 extends longitudinally within the magazine 5 for supporting the staples s in straddled relation thereacross to adapt them to advance therealong for feeding them singly to thedriving means of the machine. The rail or core 15 is fastened in the magazine 5 by welding it to the bottom :thereof or by any other suitable means. A t its forward end the'bottom wall of the core `15 is reduced in width and bent upwardly in a lug 17 (Figs.

10 of the maga- 13 for egress of the staples when driven out of the machine (Figs. 1, 4). n

7) to form a-,re- Y pierced with a hole for receiving the reduced and shouldered forward end of a rod 20. The rod 20 extends longitudinally Within the core 15 with its rearward end engaging through a hole in a lug 22 (Fig. 5) which is also bent up from the bottom of the core 15. The rearward end of the rod 20 is beveled or pointed to engage in a peripheral groove 23 formed centrally of the pivot-pin 6 (Fig. 4) for holding the pin in place. The rod 20 forms a support and track for a staple-pusher 25 slidably mounted thereon and urged forwardly therealong by a helical spring 26 surrounding the rod.

The staple-pusher 25 (Figs. 2, l0) is of usual construction with a top wall 28 and depending side flanges 29 overlying the sides of the core 15 for guiding its sliding movement therealong. Bent downwardly from the top of the pusher 25 at its front is a lug 30 formed with a circular hole through which the rod 20 extends to hold the pusher down on the core 15. The forward end of the spring 26 engages against the lug 30 on the pusher 25 for sliding it forwardly on the core 15, the spring having an additional function by serving to hold the rod 20 against release from the lugs 17 and 22. For this purpose the rearward end of the spring 26 bears against a square washer 31 perforated to receive the rod 20 and held from release therefrom by a spring-ring 32 engaging a groove in the rod. The tension of the spring 26 thus acts against the washer 31 to force the rod 20 rearwardly and maintain its pointed end in engagement with the groove 23 in the pivot-pin 6 (Fig. 5). A ngerpiece 33 sheared from the top of the pusher 25 and bent upwardly therefrom may be grasped for manually retracting the pusher in the magazine to open it for loading staples therein.

The operating lever 7 may be constructed of sheetmetal formed to provide depending sides 8 and arched top, as previously described, the side walls 8 being bent inwardly in right-angular portions 35 (Fig. 6) at its forward end without meeting at the center. For closing the space between the bent ends 35 the hand-rest 9, previously mentioned, is formed with a front wall extending between its sides which overlap the sides of the lever 7. The upper wall 37 of the hand-rest 9 lits snugly against the top of the lever 7 and is fastened thereto by a tab 38 (Fig. 2) at its rearward end inserted through a slot 39 and bent across the edge thereof on the under side. The front wall 36 of the rest 9 is perforated with a hole for receiving a screw 40 with its head seated in a counterbore 41 formed in the wall. Bearing against the inturned ends of the sides 8 of the lever 7 is an angular bracket or mounting 42 (Fig. 2) clamped thereto by the screw 40. The mounting 42 is constituted by a flat front plate 43 (Fig. 6) formed with a boss in which is a threaded hole for receiving the end of the screw 40. Extending rearwardly from the front plate 43 is a horizontal arm 44 of reduced width bent upwardly at rightangles (Fig. 2) to project through a slot 45 in the top of the lever 7 and then bent again in a rearwardly extending length 46 seated in an offset depression 47 in the top of the lever which provides a rest for the end of the arm. The horizontal length of the arm 44 mounts the staple-driver in the form of a flat blade 50 suspended from the arm by means of a transverse slot 51 adjacent its upper end through which the arm projects. The depressed portion 47 in the top of the lever 7 is formed with narrow lugs 53 which project downwardly near its end to form a stop or detent in engagement with the upper end of the driver blade 50 for locating it in operative position on the arm 44. A relatively light helical spring 55 encircling the arm 44 is arranged with one end held against a shouldered portion 56 of the arm 44 in advance of its joinder to the front plate 43 with its opposite end bearing against the driver-blade 50 to yieldingly hold its upper end engaged with the stop lugs 53. The driver-blade 50 is thus pivotally suspended to rock or cant at its lower end so as to follow a straight path during the driving stroke while the forward end of the lever 7 describes an arc as it swings about the pivot 6.

In prior art devices of the present type the staple-driver blade is arranged to slide in a narrow slot or throat at the front of the staple-core, being guided in the throat between the vertical end wall of the magazine and an abutment or wall spaced a slight distance rearwardly therefrom. This requires that the space between the walls constituting the throat or raceway through which the staples are driven be absolutely accurate in dimension for guiding the driver-blade during its descent in order to direct it in a straight course for engaging a single staple fed off from the end of the core without contact with the next succeeding staple at the rear of the leading one. Unless this extreme exactitude of dimension is maintained in the manufacture of the parts of the machine by insistence on close tolerances or dimensional limits to prevent variations in the width of the slotted throat or raceway, the driver-blade may have room to play therein so that its stroke cannot be directed accurately to engage precisely with the head of only the leading staple without interference from the next adjacent staple at the rear of the one to be driven. Such interference during the driving stroke of the blade often causes jamming of the staples in the throat of the machine with bending and distortion thereof to interrupt proper functioning of the device. In most machines of the present type a door or other means is provided for opening the throat to clear it of jammed staples and this necessitates manual attention, lost time and sometimes results in damage to the mechanism.

To overcome such diiculties and deciencies in previously used machines the present invention contemplates the provision of novel and improved means for guiding the driver-blade accurately and precisely through a straight unvarying stroke without the use of a doublesided throat for confining it in its path. For this purpose the guiding means for the staple-driver may consist in an element arranged to engage the rearward face of the blade 50 u nder resilient pressure to continuously maintain it in contact with the front wall 11 of the magazine during its reciprocation.

As one satisfactory form of construction, the guiding means for the blade 50 comprises a sheet-metal member 60 (Fig. 12) of inverted U-shape in cross-section having a flat top 61 with depending side walls 62 dimensioned to fit within the sides of the cover or operating lever 7 extending longitudinally thereof. The rearward end of the member 60 is formed with downwardly inclined ears 63 slightly offset outwardly from the sides of the member t0 adapt them to fit closely against the inner sides of the magazine 25 (Figs. 2, 3, 5, 1l). The ears 63 are provided with slightly elongated holes or slots 64 therein for receiving the pivot-pin 6 which extends across the magazine. By this form of construction the guide-member 60 is mounted to swing with the operating lever 7 about the axis of the pin 6 while being slidable longitudinally relatively to the lever. The forward ends of the side walls G2 of the member 60 are inclined downwardly from the top and terminate in straight vertical edges 65 of limited extent for engagement with the rearward face of the driver-blade 50 (Figs. 2, 3, l2). Means is provided for resiliently forcing the member 60 forward to maintain its end portions 65 pressed against the rearward face of the driver-blade 50. A helical spring 66 (Fig. 5) held at one end under an ear 67 bent down from the top wall of the lever 7 has its opposite end projecting into an opening at the end of the member 60 and engaging around a tongue 68 that projects rearwardly from the top wall thereof.

Overlying the top of the guide-member 60 within the connes of the lever 7 is an auxiliary pressure-element 70 (Figs. 3, 10) formed of sheet-metal with a top wall 71 and depending side walls 72 straddling the sides of the member 60. A plate-like member 75 (Fig. 12) welded or otherwise suitably fastened to the top of the guidemember 60 has its rearward portion offset upwardly and formed with a transverse slot `76. The forward end of the top wall of the member 70 is bent upward in a lug 77 (Fig. 3) engaging through the slot 76 to hold the member 70 in connection with the guide-member 60 at this point; the slot 76 being of suicient width to permit the member 70 to slide longitudinally. The wider portion of the member 75 projects laterally at the sides of the member 70 'with the ends disposed for engagement with detent-elements 81 (Figs. 6, 8) which project inwardly from the sides of the lever 7. The detents 81 are formed by slitting the metal and extruding it inwardly from the sides of the lever; the slits being covered and concealed from view by the sides of the hand-rest 9. A tapering spring 85 (Fig. 2) is arranged with its smaller end bearing against the top of the lever 7 and its larger end seated on the member 70 and held in place by the bottom coil of the wire engaged under fingers 86 bent upward from slots in the top of the member 70.

At the rearward end of the pressure-element 70 its sides are formed with stop-lugs 88 (Figs. 3, 10) projecting outwardly from its side walls 72 in position to engage the rounded forward ends of the sides of the yoke 4 to limit the downward motion of said element when the lever 7 is depressed. Due to this action the spring 85 is compressed to increase its tension for raising the lever 7 to withdraw the staple-driver 50 upwardly above the end of the core 15 in the magazine 5 as shown in Fig. 2. Referring to Fig. l0, the opposite sides -of the yoke 4 are indented on the outside to form slight beveled projections 90 on the inside engageable with similar projections 91 on the sides of the magazine 5 to limit the upward movement of the magazine. Normally, during the operation of the implement, the lever 7 is connected to the magazine 5 by the latch 95 (Figs. l, 9), previously mentioned, which has a fluted or roughened outer surface and overlies the outer wall of the lever. The latch 95 is slidably mounted on one side wall 8 of the' lever 7 by means of a tab 96 (Fig. 9) bent inwardly at the bottom and then upwardly and outwardly to project through a slot 97 cut through said lwall. A projecting lip 98 on the bottom of the latch 95 is adapted to engage with the detent lug 14 (Fig. 9) formed on one side wall of the magazine 5 to releasably fasten the parts together. The lever 7 may be manually disconnected from the magazine 5 by sliding the latch 95 rearwardly thereon to disengage it from the lug 14 so that the lever or cover 7 may be swung upwardly and rearwardly to open the magazine for loading staples thereinto.

The structure and arrangement of the complete implement having been described in detail, its method of operation is explained as follows: In the normal relationship of the parts of the implement (Fig. l), the driving lever 7 is releasably coupled to the magazine 15 by means of the latch 95 as above explained with the spring 85 holding these connected parts raised as the lugs 88 bear against the forward `end of the sides of the yoke 4, the spring being somewhat expanded during this relationship of ythe elements. More specifically, the spring 8'5 presses the rearward end of the element 70 down against the top of the yoke '4 to cause it to act as a lever for raising the lever 7 and the magazine 5 connected thereto. At the same time, the spring -85 acts to hold the guidemember `66 down with its forward end bearing against the tops of the staples s to serve .the dual purpose of preventing them from rising above the core 15. At this juncture the staple-driver l50 is elevated with its lower edge raised above the foremost staple advanced from the end of the core 115 and pressed against the front wall 1l of the magazine as shown in Fig. 2. It being understood that thev magazine 5 is loaded with staples s,us,ually cemented togetherin a so-called stick or refill 'S, and the pusher 25 will feed them forwardly on the core -15 under the force of the spring 26 to advance Athe foremosts one beyond the end of the core. may consist of sheets or other overlying articles, is placed across'the clinching element or anvil 3 on the base 2 (Fig. 3) and the operators hand applied to the rest 9- on the lever 7 to press the magazine 5 downward until its forward end strikes against the top of the work. The spring A35 is of suiiicient strength to adapt the lever 7 and magazine 5 to move together without changing their interrelationship. As the forward end of the magazine 5 strikes the work W its further downward motion is resisted so that the pressure on the lever 7 will continue its movement to slide the staple-driver 50 downwardly to drive a staple into the work (Fig. 3). During the descent of the driver `50 its rearward face slides across the straight edges 65 at the end of the guide-member y6i) which is urged forwardly by the tension of the spring -66 ('Figs. 3, 5). The guide-member 60 is thus caused to bear resiliently against the driver and maintain the latterr bearing against the front wall v11 of the magazine' 5. By this means the driver-blade '50 is controlled in its descent and directed in a straight course so that it will engage accurately and precisely with the top of the foremost staple fed off from the end of the core 15. Thus each stroke of ythe driver 50 is accurately controlled to prevent it from engaging with an adjacent staple at the rear of the one being driven to avoid interference there from. Due to this novel and simple construction and arrangement of the parts the driver-blade 50 is prevented from rocking or canting as its lower edge meets the staple and consequently the implement can be operated continuously to apply staples one after another without interference to avoid jamming of the staples and clogging of the machine liable to interrupt the sequence of its operation. It has been explained that the staple-driver 50 is pivotally connected to the operating lever 7 to mount it thereon with its upper end pressed against the stop-lugs '53 by the spring 55', being arranged in this manner so that as the forward end of the lever 7 swings down in an arc the driver is allowed to assume the necessary vertical relationship during its descent for driving a staple.

When the operating lever 7 is raised as shown in Fig. 2, or thrown back to uncover the magazine 15 for loading it with staples, the driver-blade `50 will be canted forwardly at the bottom. However, when after loading the magazine the lever 7 is brought down to connect it to the magazine by means of the latch the lower end of the driver will be guided into place by the inclined upper portion of the front wall 11 of the magazine and the inclined upper edges of the side walls 62 of the member f6() which form a re-entrant mouth for directing the driver through a proper course for engagement by the straight edge 65 at the end of the guide-member 60. It has been explained that when the lever 7 is released after a stapling operation it will be raised with the magazine 5 to return the parts to first position as the detent projections 9-1 make contact with the stops y90 on the ,side walls of `the yoke 4 (Fig. 10). When the -latch 95 is released from the lug 1'4 on the magazine '5 by sliding it rearwardly along the side of the lever 7 the lever may be swung back to open the magazine as the latter is held from moving upwardly with the lever.

It will be observed from the foregoing specication that the present invention provides an extremely simple yet efficient means for controlling the reciprocal motion of the staple-driver without -dependence on a doublewalled throat at the forward end of the magazine., Consequently, the parts of the machine may be manufactured without the extreme' accuracy and precision necessary when the driver-,blade is guided between two spaced walls.

In fact, by eliminating the requirement for such accurate f' machining and assembling of the parts, important economies in the cost of manufacture are accomplished andv the danger of` jamming by the staples and clogging of:

the device is avoided to improve its efficiency of operation.

The work W, which It is to be understood that while the invention is herein illustrated and described in a preferred form of construction, variations may be made therein without departing from the spirit or scope of the invention as expressed in the accompanying claims. Therefore, without limiting ourselves in this respect, we claim:

1. In a fastener-applying device comprising a hollow magazine for containing a supply of fasteners, said maga- 'zine having a transverse wall at its forward end, means for feeding the fasteners toward said wall, a driver reciprocable in sliding engagement with said wall to drive a fastener, a member mounted for movement forwardly above said magazine for positive engagement with the rearward face of the driver to hold it against said wall during a driving stroke thereof, and resilient means for operating said member.

2. In a fastener-applying implement comprising a hollow magazine for containing fasteners, said magazine having a transverse wall at its end, means for feeding the fasteners in said magazine to locate the foremast fastener bearing against said forward wall, a driver reciprocable in sliding engagement with said wall to drive a fastener out of the magazine, a guiding member for said driver movably mounted on the magazine, and resilient means acting on said guiding member to engage it with the driver to hold the latter bearing against said Wall.

3. In a fastener-applying implement comprising a channel-shaped magazine for containing a supply of fasteners, an abutment at the forward end of said magazine, 4means to feed the fasteners forwardly in the magazine to locate the foremost one against said abutment, a driver reciprocable in sliding engagement with said abutment for driving a fastener from the magazine, a member mounted on the magazine above the fasteners therein, and resilient means for sliding said member forward to engage its end with said driver to hold it in sliding engagement with the abutment for accurately guiding it to operate on a single fastener without interference from an adjacent one.

4. In a stapling appliance comprising a channel-shaped magazine for containing staples, said magazine closed at its end by a transverse wall, means for feeding the staples forwardly in the magazine to position the foremost one in contact with said wall, a driver reciprocable in sliding engagement with the rearward face of said wall, a holddown member extending longitudinally above the staples in the magazine to prevent them from rising and slidable therealong, and a spring acting on said member to engage its forward end with the driver to constantly maintain it pressed against the rearward face of said wall for accurately engaging the top of the foremost staple in the magazine in driving it therefrom.

5. In a device of the type indicated comprising a channel-shaped magazine for containing staples, said magazine having a transverse front wall connecting its sides, means for feeding the staples in said magazine to advance the foremost one into driving position against the front wall of the magazine, a staple-driver mounted for reciprocation across the end of the magazine in sliding engagement with the rearward face of said front wall, a holddown member pivotally mounted at the rearward end of the magazine and extending forwardly above the staples to prevent them from rising therein, said hold-down member being slidable longitudinally of the magazine, and a spring engaging said member for sliding it forward and engaging its end with the driver to maintain the latter in guiding contact with the rearward face of said wall.

6. In a device according to claim 5, a pivot-pin extending transversely of the magazine, a slot in the end of said hold-down member through which said pin projects for mounting said member to pivot thereon and to move longitudinally of said magazine, and a spring in the magazine engaging said member to move it toward the stapledriver for forcing it against the rearward face of the wall at the front of the magazine.

7. In a device in accordance with claim 5, a lever pivoted to the magazine and carrying the staple-driver for reciprocating it, said hold-down member being movable about said pivot connection by and with said lever, and said spring being anchored to said lever and operative to slide said hold-down member to engage it with said driver.

8. In a device of the type indicated, a magazine for containing staples, a transverse wall at the forward end of said magazine, a core extending longitudinally of the magazine for mounting the staples to slide therealong, an operating lever pivoted to the rearward end of said magazine, a driver-blade, means for pivotally mounting said driver-blade on said lever to adapt it to slide vertically between the front wall of the magazine and the end of the staple-core, a member pivotally connected with the lever and slidable longitudinally thereof, and resilient means for urging said member forwardly to engage its end with the rearward face of said driver-blade to maintain it in sliding contact with `the forward wall of the magazine during its reciprocaton by said operating lever.

9. In a device of the type indicated, a U-shaped magazine for containing staples, a transverse wall at the forward end of said magazine, a staple-core extending longitudinally within the magazine, a lever pivoted to swing down on the magazine to close its open top, a driverblade pivoted at its upper end to the operating lever to adapt it to slide vertically along the rearward face of said forward wall of the magazine, a hold-down member mounted above the staple-core in said magazine and slidable longitudinally thereof, and means for resiliently urging said hold-down member forwardly to maintain its end bearing against the rearward face of the driver to direct it in a vertical path in sliding engagement with the forward wall of the magazine.

l0. In a device of the type indicated, a base, a yoke on said base having opposite side walls, a U-shaped magazine pivoted to the sides of said yoke, a transverse wall at the front of the magazine, a lever pivoted to said yoke to swing relatively to said magazine, a driver-blade pivotally supported on the operating lever to adapt it to slide down in the magazine, a guiding member pivoted to the operating lever and adapted to slide forwardly to engage its end with said driver-blade to maintain the latter in sliding contact with the front wall of the magazine, means for releasably connecting the magazine with said operating lever, a pressure-member extending longitdinally above said guiding member and pivotally connected thereto at its forward end, and a spring on the operating lever bearing against said pressure-member to urge it downwardly into engagement with the ends of the side walls of the yoke to compress said spring for raising the lever and magazine after completion of a downward stroke of the driver-blade.

ll. In a device of the type indicated, a hollow magazine for containing fasteners, a transverse wall at the front of the magazine, an operating lever pivoted to said magazine, an arm at the forward end of said lever, a driver-blade formed with a slot for pivotally mounting it on said arm, a stop-lug on the operating lever, a spring for pressing the upper end of said driver-blade against said stop-lug, a guide-member pivotally connected to said operating lever at one end and adapted to slide forward relatively thereto, and resilient means for sliding said guide-member forward to cause its end to bear against the driver-blade to maintain the latter in sliding engagement with the front wall of the magazine.

References Cited in the le of this patent UNITED STATES PATENTS 2,247,292 Eps June 2.4, 1941 

